Turn signal functions intermittently

I'm glad to be a new member of this forum! Tacos are the best truck ever built, in my humble opinion.

I'm hoping somebody can help.

I'm on an extended visit to St. Louis where a friend has given me access to her 98 reg cab taco. The truck runs great, but about half the time the turn signal does not work. When it doesn't work whether I signal left or right nothing happens, nothing. When it does work, there is no buzzing or out of sorts clicking; it works perfect. When the turn signal is not working the light switch (brights too) work fine.

As I only have a few tools (enough to do the fix but not diagnose the issue), I'm wondering if somebody could help me diagnose the faulty switch, wiring, or relay? Has anybody else encountered this issue or could diagnose it with confidence?